JP2015050761A - Piezoelectric vibration piece, piezoelectric device, method for manufacturing piezoelectric vibration piece, and method for manufacturing piezoelectric device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibration piece whose manufacturing costs were reduced by increasing the number of piezoelectric vibration pieces obtainable from one wafer, and a method for manufacturing a piezoelectric vibration piece.SOLUTION: A method for manufacturing a piezoelectric vibration piece 100 which includes a base part 110, a first arm part 120 formed on the base part, and a second arm part 130 formed on the first arm part and in which one end of the first arm part is connected to one end of the second arm part comprises the steps of: forming a first protective film layer; forming a first silicon layer constituting the first arm part; forming a first piezoelectric element 140; forming a second protective film layer; forming a second silicon layer constituting the first arm part; forming a second piezoelectric element 150; and removing all the first protective film layer and the second protective film layer by etching.

Description

  The present invention relates to a piezoelectric vibrating piece, a piezoelectric device, a method for manufacturing a piezoelectric vibrating piece, and a method for manufacturing a piezoelectric device, which are formed so that arms overlap vertically.

  A tuning fork vibrator having a plurality of arm portions, a base portion to which one end of the arm portion is connected, and a piezoelectric element formed on one surface of the arm portion is known. The piezoelectric element includes a piezoelectric film and a pair of electrodes formed so as to sandwich the piezoelectric film. For example, Patent Document 1 discloses a tuning fork vibrator in which three and five arms are formed. In such a tuning fork vibrator, a decrease in temperature characteristics due to miniaturization is suppressed, and the Q value is increased by alternately vibrating up and down adjacent arm portions with an odd number of arm portions.

JP 2009-5023 A

  However, in Patent Document 1, since the plurality of arm portions of the piezoelectric vibrating piece are formed side by side, the area of the plane of the piezoelectric vibrating piece is increased, and the number of piezoelectric vibrating pieces that can be taken from one wafer is reduced. There is a problem that the manufacturing cost increases.

  In the present invention, by reducing the plane area of the piezoelectric vibrating piece, the number of piezoelectric vibrating pieces that can be taken from one wafer is increased, and the manufacturing cost of the piezoelectric vibrating piece, the piezoelectric device, and the manufacturing method of the piezoelectric vibrating piece are reduced. And it aims at providing the manufacturing method of a piezoelectric device.

  A method of manufacturing a piezoelectric vibrating piece according to a first aspect includes a base portion formed in a planar shape, a first arm portion formed on the base portion and extending in a first direction, and formed on the first arm portion and extending in the first direction. And a second arm part, wherein one end of the first arm part is connected to one end of the base part and the second arm part. In the method for manufacturing a piezoelectric vibrating piece, a first protective film layer forming step of forming a first protective film layer on a substrate wafer on which a plurality of base parts are formed, and a first arm portion is formed on the first protective film layer. A first silicon layer forming step of forming a first silicon layer; a first lower electrode film formed on the first silicon layer; a first piezoelectric film formed on the first lower electrode film; and a first piezoelectric film A first piezoelectric element forming step for forming a first piezoelectric element constituted by a first upper electrode film formed on the body film; and a second for forming a second protective film layer on the first piezoelectric element. A protective film layer forming step, a second silicon layer forming step of forming a second silicon layer constituting the second arm portion on the second protective film layer, and a second lower electrode formed on the second silicon layer Film, second piezoelectric film formed on second lower electrode film, and second upper electrode formed on second piezoelectric film A second piezoelectric element forming step of forming a second piezoelectric element configured, and a protective layer removing step of removing by etching all the first protective layer and the second protective layer by.

  According to a second aspect of the method for manufacturing a piezoelectric vibrating piece, in the first aspect, the first piezoelectric element and the second piezoelectric element formed on each piezoelectric vibrating piece are formed in the same area and shape, and are vertically aligned with each other. Are formed so as to overlap the whole.

  In the method for manufacturing a piezoelectric vibrating piece according to the third aspect, in the first aspect, the first arm portion is formed longer in the first direction than the second arm portion.

  According to a fourth aspect of the method of manufacturing a piezoelectric vibrating piece, according to the first to third aspects, the piezoelectric vibrating piece is formed in a state where the piezoelectric vibrating piece is connected to the substrate wafer via the connecting portion, and the connecting portion is formed after the protective film layer removing step. A piezoelectric vibrating piece separating step for separating the piezoelectric vibrating piece from the substrate wafer by folding the piezoelectric vibrating piece.

  In the piezoelectric device manufacturing method according to the fifth aspect, the piezoelectric vibrating piece includes a vibrating portion including the base, the first arm portion, and the second arm portion, and a frame formed to surround the vibrating portion. And a connecting portion that connects the vibrating portion and the frame portion, and the piezoelectric vibrating piece is formed between the base plate and the lid plate. Further, according to the first to third aspects of the manufacturing method of the piezoelectric device, the base plate wafer for joining the substrate wafer and the base plate wafer on which the base plate is formed after the piezoelectric vibrating piece is formed on the substrate wafer. A bonding step, a lid plate wafer bonding step for bonding the substrate wafer and the lid plate wafer on which the lid plate is formed, and a cutting step for cutting the substrate wafer, the base plate wafer, and the lid plate wafer.

  A piezoelectric vibrating piece according to a sixth aspect is a base portion formed in a planar shape and formed to extend in a first direction, one end of which is fixed on the base portion and the other end is not fixed. A first arm, a second arm that is formed to extend in the first direction, has one end fixed on one end of the first arm, and the other end is not fixed; A first lower electrode film formed on one surface of one arm, a first piezoelectric film formed on the first lower electrode film, and a first upper electrode film formed on the first piezoelectric film A first piezoelectric element comprising: a second lower electrode film formed on one surface of the second arm, a second piezoelectric film formed on the second lower electrode film, and a second piezoelectric And a second piezoelectric element composed of a second upper electrode film formed on the body film.

  In the sixth aspect, the piezoelectric vibrating piece according to the seventh aspect is formed such that the first piezoelectric element and the second piezoelectric element are formed in the same area and shape, and overlap each other in the vertical direction.

  In the sixth aspect, the piezoelectric vibrating piece according to the eighth aspect is formed such that the first arm portion is longer in the first direction than the second arm portion.

  A piezoelectric resonator element according to a ninth aspect includes, in the sixth to eighth aspects, a base, a first arm, a second arm, a first piezoelectric element, and a second piezoelectric element. It has a vibration part to be formed, a frame part formed so as to surround the periphery of the vibration part, and a connecting part for connecting the vibration part and the frame part.

  A piezoelectric device according to a tenth aspect includes the piezoelectric vibrating piece according to the ninth aspect, a base plate bonded to one surface of the frame portion, and a lid plate bonded to the other surface of the frame portion.

  According to the piezoelectric vibrating piece and the method of manufacturing the piezoelectric vibrating piece of the present invention, the number of piezoelectric vibrating pieces that can be taken from one wafer can be increased by reducing the plane area of the piezoelectric vibrating piece, thereby reducing the manufacturing cost. .

FIG. 4A is a perspective view of the piezoelectric vibrating piece 100. FIG. (B) is AA sectional drawing of Fig.1 (a). 3 is a plan view of a wafer W100 on which a piezoelectric vibrating piece 100 is formed. FIG. 5 is a flowchart showing a manufacturing process of the piezoelectric vibrating piece 100. 5 is a flowchart showing a manufacturing process of the piezoelectric vibrating piece 100. 5 is a flowchart showing a manufacturing process of the piezoelectric vibrating piece 100. 5 is a flowchart showing a manufacturing process of the piezoelectric vibrating piece 100. 5 is a flowchart showing a manufacturing process of the piezoelectric vibrating piece 100. 5 is a flowchart showing a manufacturing process of the piezoelectric vibrating piece 100. 2 is an exploded perspective view of a piezoelectric device 200. FIG. FIG. 6A is a plan view of the piezoelectric vibrating piece 230. (B) is CC sectional drawing of FIG. 5 is a flowchart illustrating a method for manufacturing the piezoelectric device 200. It is a top view of the substrate wafer W230. It is a top view of base board wafer W220. It is a top view of the lid board wafer W210. FIG. 6A is a perspective view of the piezoelectric vibrating piece 300. FIG. (B) is DD sectional drawing of Fig.15 (a).

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings. It should be noted that the scope of the present invention is not limited to these forms unless otherwise specified in the following description.

(First embodiment)
<Configuration of Piezoelectric Vibrating Piece 100>
FIG. 1A is a perspective view of the piezoelectric vibrating piece 100. The piezoelectric vibrating piece 100 includes a base 110, a first arm 120 having one end fixed on the base 100, a second arm 130 having one end fixed on the first arm 120, The first piezoelectric element 140 formed on the first arm 120 and the second piezoelectric element 150 formed on the second arm 130 are formed. In the following description, the direction in which the first arm portion 120 and the second arm portion 130 extend is the Y-axis direction, the direction in which the base portion 110, the first arm portion 120, and the second arm portion 130 overlap is the Z-axis direction, and the Y-axis direction. The direction orthogonal to the Z-axis direction is taken as the X-axis direction.

  The base 110 is formed in a planar shape extending in the Y-axis direction, and an external electrode 171 and an external electrode 172 are formed on the surface of the base 110 on the −Z-axis side. The first arm 120 is a free end whose end on the -Y axis side is fixed on the base 110 and whose end on the + Y axis side is not fixed. The second arm part 130 is a free end whose end on the −Y axis side is fixed on the first arm part 120 and whose end on the + Y axis side is not fixed. A first piezoelectric element 140 is formed on the surface of the first arm 120 on the + Z-axis side, and a second piezoelectric element 150 is formed on the surface of the second arm 130 on the + Z-axis side. A pair of electrodes are drawn out from the piezoelectric element 140 and the second piezoelectric element 150, respectively, and are externally connected through the base electrode 110, the first arm part 120, and the second arm part 130 through the through electrode 161 and the through electrode 162. The electrode 171 (see FIG. 1B) and the external electrode 172 are electrically connected.

  FIG.1 (b) is AA sectional drawing of Fig.1 (a). The first piezoelectric element 140 includes a first lower electrode film 141 formed on the first arm 120, a first piezoelectric film 142 formed on the first lower electrode film 141, and a first piezoelectric film. 142, and a first upper electrode film 143 formed on 142. The second piezoelectric element 150 includes a second lower electrode film 151 formed on the second arm 130, a second piezoelectric film 152 formed on the second lower electrode film 151, and a second piezoelectric element. And a second upper electrode film 153 formed on the body film 152. In the piezoelectric vibrating piece 100, the first upper electrode film 143 and the second lower electrode film 151 are electrically connected via the through electrode 161, and further formed on the −Y axis side of the −Z axis side surface of the substrate 110. The external electrode 171 is electrically connected. In addition, the first lower electrode film 141 and the second upper electrode film 153 are electrically connected through the through electrode 162, and the external electrode 172 formed on the + Y-axis side of the −Z-axis side surface of the substrate 110. Is electrically connected. The through electrode 162 and the external electrode 172 are such that the through electrode 162 is drawn out to the −Z axis side surface of the substrate 110, and the −Z axis side surface of the substrate 110 is drawn from the −Y axis side to the + Y axis side. Connected by In FIG. 1B, a SiN film 184 (see FIG. 3C) described later is omitted.

  In the piezoelectric vibrating piece 100, when an alternating voltage is applied to the external electrode 171 and the external electrode 172, the first arm unit 120 and the second arm unit 130 vibrate up and down in the Z-axis direction. In the first piezoelectric element 140 and the second piezoelectric element 150, the potentials of the upper electrode and the lower electrode are reversed, so that the vibration directions of the first arm portion 120 and the second arm portion 130 are reversed. That is, when the first arm portion 120 vibrates toward the + Z axis side, the second arm portion 130 vibrates in the −Z axis direction, and when the first arm portion 120 vibrates toward the −Z axis side, the second arm portion vibrates. The portion 130 vibrates in the + Z axis direction.

<Method for Manufacturing Piezoelectric Vibrating Piece 100>
FIG. 2 is a plan view of the substrate wafer W110 on which the piezoelectric vibrating piece 100 is formed. A plurality of piezoelectric vibrating reeds 100 are formed side by side in the X-axis direction and the Y-axis direction on the substrate wafer W110. A through groove 181 is formed around each piezoelectric vibrating piece 100. Further, each piezoelectric vibrating piece 100 is connected to the substrate wafer W <b> 110 by a connecting portion 182 formed on the −Y axis side of each piezoelectric vibrating piece 100.

  3 to 8 are flowcharts showing the manufacturing process of the piezoelectric vibrating piece 100. 3 to 7, partial sectional views of the substrate wafer W110 are shown on the right side of each step. This partial cross-sectional view is a cross-sectional view including the BB cross section of FIG. In some steps, an enlarged plan view of a dotted line 190 of the substrate wafer W110 of FIG. 2 is shown together with a partial cross-sectional view of the wafer W100.

  In step S101 of FIG. 3, the through groove 181 and the through groove 183 are formed in the substrate wafer W110. FIG. 3A is a partial cross-sectional view of the substrate wafer W110 included in a part of the BB cross section of FIG. FIG. 3B is an enlarged plan view of the substrate wafer W110 taken along the dotted line 190 in FIG. The substrate wafer W110 is a wafer constituting the substrate 110, and is formed of polycrystalline silicon. In step S101, the through groove 181 and the through groove 183 for forming the through electrode 161 and the through electrode 162 are formed in the substrate wafer W110 by etching.

  In step S102, a silicon nitride (SiN) film 184 is formed on the substrate wafer W110. FIG. 3C is a partial cross-sectional view of the substrate wafer W110 on which the SiN film 184 is formed. Various films are formed on the substrate wafer W110. The SiN film 184 is formed so as to cover the substrate wafer W110 so that the substrate wafer W110 is not damaged in the process of forming these films. The SiN film 184 is formed, for example, by sputtering SiN on the substrate wafer W110. Step S102 is a SiN film forming process.

  In step S103, the first protective film layer 185 is formed on the substrate wafer W110. FIG. 3D is a partial cross-sectional view of the substrate wafer W110 on which the first protective film layer 185 is formed. The first protective film layer 185 is formed, for example, by sputtering PSG (phosphosilicate glass) on the surface on the + Z-axis side of the substrate wafer W110. Step S103 is a first protective film layer forming step.

  In step S104, the first protective film layer 185 is etched. FIG. 3E is a partial cross-sectional view of the substrate wafer W110 in which the first protective film layer 185 has been etched. FIG. 3F is an enlarged plan view of the substrate wafer W110 in which the first protective film layer 185 is etched. In step S104, the first protective film layer in the region where the first arm 120 and the substrate 110 are in contact with each other in the region other than the region where the piezoelectric vibrating piece 100 is formed and the region where the piezoelectric vibrating piece 100 is formed. 185 is removed by etching. In the etching in step S104, for example, a photoresist (not shown) is applied to the surface of the first protective film layer 185, and the photoresist is exposed and developed through a predetermined mask (not shown), thereby exposing the photoresist. The first protective film layer 185 is etched by hydrofluoric acid which is an aqueous solution of hydrogen fluoride. Step S104 is a first protective film layer etching step.

  In step S105 of FIG. 4, the first silicon layer 186 is formed. FIG. 4A is a partial cross-sectional view of the substrate wafer W110 on which the first silicon layer 186 has been formed. The first silicon layer 186 is formed by depositing silicon over the entire surface on the + Z-axis side of the substrate wafer W110 by LPCVD (low pressure chemical vapor deposition). Step S105 is a first silicon layer forming step.

  In step S106, the first silicon layer 186 is etched. FIG. 4B is a partial cross-sectional view of the substrate wafer W110 in which the first silicon layer 186 has been etched. FIG. 4C is an enlarged plan view of the substrate wafer W110 in which the first silicon layer 186 has been etched. The first silicon layer 186 is etched in a region where the through groove 181, the through groove 183, and the piezoelectric vibrating piece 100 of the substrate wafer W <b> 110 are not formed. In the etching of step S106, for example, a photoresist is applied to the surface of the first silicon layer 186, the photoresist is exposed and developed through a predetermined mask, and the first silicon layer 186 in the region exposed from the photoresist is removed by TMAH ( Etching with a weak alkaline etchant such as tetramethylammonium hydroxide). Thereby, the 1st arm part 120 is formed. Step S106 is a first silicon layer etching step.

  In step S107, the first metal film 187 is formed on the substrate wafer W110. FIG. 4D is a partial cross-sectional view of the substrate wafer W110 on which the first metal film 187 has been formed. The first metal film 187 is made of, for example, molybdenum (Mo). The first metal film 187 is formed on the entire surface of the substrate wafer W110 by, for example, sputtering. Step S107 is a first metal film forming step.

  In step S108 of FIG. 5, the first metal film 187 is etched. FIG. 5A is a partial cross-sectional view of the substrate wafer W110 in which the first metal film 187 has been etched. FIG. 5B is an enlarged plan view of the substrate wafer W110 in which the first metal film 187 has been etched. The first metal film 187 is formed, for example, by applying a photoresist to the surface of the first metal film 187, exposing and developing the photoresist through a predetermined mask, and exposing a region formed of nitric acid and phosphoric acid. Etching is performed with a mixed solution or the like. As a result, the first lower electrode 141, the external electrodes 171, 172, and the through electrodes 161, 162 are partially formed on the substrate wafer W110. In FIGS. 5A and 5B, the hatching of the first metal film 187 is changed in accordance with FIG. 1B. Step S107 is a first metal film etching step.

In step S109, the piezoelectric film 188 is formed. FIG. 5C is a partial cross-sectional view of the substrate wafer W110 on which the piezoelectric film 188 is formed. The piezoelectric film 188 is made of, for example, ZnO, AlN, PZT, LiNbO ₃ , or KNbO ₃ . The piezoelectric film 188 is formed on the surface on the + Z-axis side of the substrate wafer W110 by sputtering, for example. Step S109 is a piezoelectric film forming step.

  In step S110, the piezoelectric film 188 is etched. FIG. 5D is a partial cross-sectional view of the substrate wafer W110 in which the piezoelectric film 188 has been etched. FIG. 5E is an enlarged plan view of the substrate wafer W110 in which the piezoelectric film 188 has been etched. In the piezoelectric film 188, for example, a photoresist is applied to the surface of the piezoelectric film 188, and a region exposed from the photoresist by exposing and developing the photoresist through a predetermined mask is etched. When AlN is used for the piezoelectric film 188, for example, tetramethylammonium hydroxide (TMAH) can be used as an etching solution. Thereby, the first piezoelectric film 142 is formed on the substrate wafer W110. Step S110 is a piezoelectric film etching process.

  In step S111 of FIG. 6, the second metal film 189 is formed. FIG. 6A is a partial cross-sectional view of the substrate wafer W110 on which the second metal film 189 is formed. Similar to the first metal film 187, the second metal film 189 is made of, for example, molybdenum (Mo). The second metal film 189 is formed on the + Z-axis side surface of the substrate wafer W110 by sputtering. Step S111 is a second metal film forming step.

  In step S112, the second metal film 189 is etched. FIG. 6B is a partial cross-sectional view of the substrate wafer W110 where the second metal film 189 has been etched. FIG. 6C is an enlarged plan view of the substrate wafer W110 in which the second metal film 189 has been etched. The second metal film 189 is formed, for example, by applying a photoresist to the surface of the second metal film 189, exposing and developing the photoresist through a predetermined mask, and exposing the region from the photoresist to a mixture of nitric acid and phosphoric acid. Etching is performed with a mixed solution or the like. Thereby, the first upper electrode 143 is formed on the substrate wafer W110. Step S112 is a second metal film etching step. Steps S107 to S112 are a first piezoelectric element forming process for forming the first piezoelectric element 140.

  In step S113, the second protective film layer 191 is formed. FIG. 6D is a partial cross-sectional view of the substrate wafer W110 on which the second protective film layer 191 is formed. The second protective film layer 191 is formed by sputtering PSG on the + Z-axis side surface of the substrate wafer W110 in the same manner as in the first protective film layer forming step (see step S103). Step S113 is a second protective film forming step.

  In step S114, the second protective film layer 191 is etched. FIG. 6E is a partial cross-sectional view of the substrate wafer W110 in which the second protective film layer 191 has been etched. In the etching in step S114, for example, a photoresist (not shown) is applied to the surface of the second protective film layer 191, and the photoresist is exposed and developed through a predetermined mask (not shown), thereby exposing the photoresist. The second protective film layer 191 is etched by hydrofluoric acid which is an aqueous solution of hydrogen fluoride. Step S114 is a second protective film layer etching step.

  In step S115 of FIG. 7, the second silicon layer 192 is formed. FIG. 7A is a partial cross-sectional view of the substrate wafer W110 on which the second silicon layer 192 is formed. The second silicon layer 192 is formed by depositing silicon on the entire surface on the + Z-axis side of the substrate wafer W110 by LPCVD. Step S115 is a second silicon layer forming step.

  In step S116, the second silicon layer 192 is etched. FIG. 7B is a partial cross-sectional view of the substrate wafer W110 in which the second silicon layer 192 has been etched. FIG. 7C is an enlarged plan view of the substrate wafer W110 in which the second silicon layer 192 is etched. In the second silicon layer 192, the region of the substrate wafer W <b> 110 where the through groove 181, the through groove 183, and the piezoelectric vibrating piece 100 are not formed is etched. In the etching in step S116, for example, a photoresist is applied to the surface of the second silicon layer 192, the photoresist is exposed and developed through a predetermined mask, and the second silicon layer 192 in the region exposed from the photoresist is removed by TMAH ( Etching with a weak alkaline etchant such as tetramethylammonium hydroxide). Thereby, the 2nd arm part 130 is formed. Step S116 is a second silicon layer etching process.

  In step S117, the second piezoelectric element 150 is formed. FIG. 7D is a partial cross-sectional view of the substrate wafer W110 on which the second piezoelectric element 150 is formed. Similar to the first piezoelectric element 140, the second piezoelectric element 150 is formed by performing the same processes as in steps S107 to S112. Step S117 is a second piezoelectric element forming step.

  In step S118 of FIG. 8, the first protective film layer 185 and the second protective film layer 191 are removed by etching. FIG. 8A is a partial cross-sectional view of the substrate wafer W110 from which the first protective film layer 185 and the second protective film layer 191 have been etched away. The first protective film layer 185 and the second protective film layer 191 are removed by etching with hydrofluoric acid which is an aqueous solution of hydrogen fluoride. Since PSG constituting the first protective film layer 185 and the second protective film layer 191 is easily etched with hydrofluoric acid, the first protective film layer 185 and the second protective film layer 191 exposed on the side surface of the piezoelectric vibrating piece 100 are used. Thus, the entire first protective film layer 185 and second protective film layer 191 can be easily removed. Step S118 is a protective film layer removing step.

  In step S119, the piezoelectric vibrating piece 100 is folded off from the substrate wafer W110. FIG. 8B is a cross-sectional view of the piezoelectric vibrating piece 100 folded from the substrate wafer W110. Each piezoelectric vibrating piece 100 is separated from the substrate wafer W <b> 110 by folding the connecting portion 182. Thereby, each piezoelectric vibrating piece 100 is individually separated from the substrate wafer W110. Step S119 is a piezoelectric vibrating piece separating step.

  In the conventional piezoelectric vibrating piece, since a plurality of arm portions are formed in parallel, the area of the plane of the piezoelectric vibrating piece is increased, and the number of piezoelectric vibrating pieces that can be manufactured from one wafer is reduced. On the other hand, the piezoelectric vibrating piece 100 can be formed so that the area of the plane is reduced by forming the arm portions in the vertical direction (Z-axis direction) of the piezoelectric vibrating piece. Thereby, the number of piezoelectric vibrating reeds that can be manufactured from one wafer can be increased, and an increase in manufacturing cost can be suppressed.

(Second Embodiment)
The piezoelectric vibrating piece may be formed as a piezoelectric device by bonding the base plate and the lid plate to the piezoelectric vibrating piece in a state where the piezoelectric vibrating piece is connected to the wafer. Hereinafter, a piezoelectric device 200 formed as a piezoelectric device will be described. Moreover, in the following description, the same part as 1st Embodiment is attached | subjected with the same number as 1st Embodiment, and the description is abbreviate | omitted.

<Configuration of Piezoelectric Device 200>
FIG. 9 is an exploded perspective view of the piezoelectric device 200. The piezoelectric device 200 is formed by a base plate 220, a lid plate 210, and a piezoelectric vibrating piece 230. The piezoelectric vibrating piece 230 is formed by a vibrating portion 231, a frame portion 232, and a connecting portion 233 (see FIG. 10A). Although no external electrode is formed on the vibrating portion 231, other shapes are formed in substantially the same shape as the piezoelectric vibrating piece 100. In addition, a frame part 232 is formed so as to surround the vibration part 231, and the vibration part 231 and the frame part 232 are connected by a connection part 233.

  A base plate 220 is disposed on the −Z-axis side surface of the piezoelectric vibrating piece 230. A recess 221 that is recessed in the −Z-axis direction is formed on the surface on the + Z-axis side of the base plate 220, and a bonding surface 222 that is bonded to the frame portion 232 is formed around the recess 221. Further, castellations 223 are formed on the side surfaces of the four corners of the base plate 220 so as to be recessed inside the base plate 220. A pair of external electrodes 224 are formed on the surface on the −Z-axis side of the base plate 220, and the external electrodes 224 are disposed around the castellation 223 on the surface on the + Z-axis side of the base plate 220 via the castellation 223. A connection electrode 225 that is electrically connected to is formed.

  A lid plate 210 is disposed on the surface on the + Z-axis side of the piezoelectric vibrating piece 230. A concave portion 211 that is recessed in the + Z-axis direction is formed on the surface on the −Z-axis side of the lid plate 210, and a joint surface 212 that is joined to the frame portion 232 is formed around the concave portion 211.

  FIG. 10A is a plan view of the piezoelectric vibrating piece 230. In the piezoelectric vibrating piece 230, a through groove 234 that penetrates the piezoelectric vibrating piece 230 in the Z-axis direction is formed between the vibrating portion 231 and the frame portion 232 surrounding the vibrating portion 231. The vibrating portion 231 and the frame portion 232 are connected to each other by connecting portions 233 extending in the −Y-axis direction from both ends of the −Y-axis side of the vibrating portion 231. A pair of extraction electrodes 235 are extracted from the vibrating portion 231, and each extraction electrode 235 passes through the connection portion 233, the + X-axis side on the + Y-axis side of the surface on the −Z-axis side of the frame portion 232, and the −Z-axis It is pulled out to the -X-axis side on the -Y-axis side of the side surface.

  FIG.10 (b) is CC sectional drawing of FIG. In the piezoelectric device 200, the lid plate 210 is bonded to the + Y axis side of the frame portion 232 via the sealing material 240, and the base plate 220 is bonded to the −Y axis side surface via the sealing material 240. Similar to the piezoelectric vibrating piece 100, the vibrating unit 231 includes a base 110, a first arm unit 120, and a second arm unit 130, and the first arm unit 120 and the second arm unit 130 have a first piezoelectric element, respectively. 140 and the second piezoelectric element 150 are formed. The frame portion 232 includes a first frame portion 232a formed at the same time as the base portion 110, a second frame portion 232b formed at the + Z-axis side of the first frame portion 232a and formed at the same time as the first arm portion 120, The third frame portion 232c is formed on the + Z-axis side of the second frame portion 232b and is formed at the same time as the second arm portion 130. Further, the base 110 and the first frame portion 232 a are connected by a connecting portion 233 that is formed simultaneously with the base 110.

<Method for Manufacturing Piezoelectric Device 200>
FIG. 11 is a flowchart illustrating a method for manufacturing the piezoelectric device 200. Hereinafter, a method of manufacturing the piezoelectric device 200 will be described with reference to FIG.

  In step S201 of FIG. 11, a substrate wafer W230 is prepared. A plurality of piezoelectric vibrating pieces 230 are formed on the substrate wafer W230. The manufacturing process of the substrate wafer W230 can be formed by substantially the same process as step S101 in FIG. 3 to step S118 in FIG.

  FIG. 12 is a plan view of the substrate wafer W230. On the substrate wafer W230, a plurality of piezoelectric vibrating pieces 230 are formed side by side in the X-axis direction and the Y-axis direction. In addition, a scribe line 241 that is a line indicating a location where the wafer is cut in step S206 described below is shown between adjacent piezoelectric vibrating pieces 230. Each piezoelectric vibrating piece 230 is formed with a vibrating portion 231, a frame portion 232, and a connecting portion 233, and a first piezoelectric element 140, a second piezoelectric element 150, and an extraction electrode 235 are formed.

  In step S202, a base plate wafer W220 is prepared. A plurality of base plates 220 are formed on the base plate wafer W220. Step S202 is a base plate wafer preparation process.

  FIG. 13 is a plan view of the base plate wafer W220. A plurality of base plates 220 are formed on the base plate wafer W220, and each base plate 220 is formed side by side in the Y-axis direction and the X-axis direction. A recess 221 is formed on the surface on the + Z-axis side of each base plate 220, and a joint surface 222 is formed so as to surround the recess 221. A scribe line 241 is shown between the base plates 220 adjacent to each other. Furthermore, a through-hole 242 that penetrates the base plate wafer W220 in the Z-axis direction is formed at the intersection of the scribe line 241 extending in the X-axis direction and the scribe line 241 extending in the Y-axis direction. The through hole 242 becomes a castellation 223 after the base plate wafer W <b> 220 is cut by the scribe line 241. In addition, a connection electrode 225 is formed around the + Z axis side of the through hole 242, and an external electrode 224 is formed on the surface of each base plate 220 on the −Z axis side, and the connection electrode 225 and the external electrode are formed. 224 are electrically connected to each other through a through hole 242.

  In step S203, a lid plate wafer W210 is prepared. A plurality of lid plates 210 are formed on the lid plate wafer 210. Step S203 is a lid plate wafer preparation process.

  FIG. 14 is a plan view of the lid plate wafer W210. A plurality of lid plates 210 are formed on the lid plate wafer W <b> 210, and a recess 211 is formed on the surface of each lid plate 210 on the −Z axis side. The lid plate 210 is formed side by side in the X-axis direction and the Y-axis direction, and a scribe line 241 is shown between the adjacent lid plates 210.

  In step S204, the substrate wafer W230 and the base plate wafer W220 are bonded to each other. The substrate wafer W230 and the base plate wafer W220 are bonded to each other by being overlapped via the sealing material 240 so that the scribe lines 241 overlap each other. Step S204 is a base plate wafer bonding step.

  In step S205, the substrate wafer W230 and the lid plate wafer W210 are bonded to each other. Here, the bonding is performed by overlapping each other through the sealing material 240 so that the scribe lines 241 overlap each other. Step S205 is a lid plate wafer bonding process.

  In step S206, the substrate wafer W230, the base plate wafer W220, and the lid plate wafer W210 are cut. The cutting is performed by dicing along a scribe line 241 of the wafer. Thereby, the piezoelectric device 200 is divided | segmented separately. Step S206 is a cutting process.

  Also in the piezoelectric device 200, since the arm portion is formed side by side in the Z-axis direction, the area of the XY plane of the vibrating portion 231 can be reduced, so that the area of the XY plane of the piezoelectric vibrating piece 230 is reduced. Can do. Thereby, since many piezoelectric vibrating reeds 230 can be formed with one wafer, the manufacturing cost of a piezoelectric device can be held down.

(Third embodiment)
In the piezoelectric vibrating piece, the first arm portion may be formed longer than the second arm portion. Hereinafter, the piezoelectric vibrating piece 300 in which the length of the first arm portion is longer than the length of the second arm portion will be described. Moreover, in the following description, the same part as 1st Embodiment is attached | subjected with the same number as 1st Embodiment, and the description is abbreviate | omitted.

<Configuration of Piezoelectric Vibrating Piece 300>
FIG. 15A is a perspective view of the piezoelectric vibrating piece 300. The piezoelectric vibrating piece 300 is formed on the base 110, the first arm 120, the second arm 330, the first piezoelectric element 140 formed on the first arm 120, and the second arm 330. The second piezoelectric element 350 is formed. On the + Z-axis side of the first arm portion 120, a second arm portion 330 that is shorter in the Y-axis direction than the first arm portion 120 is formed. Accordingly, the second arm portion 330 is not formed so as to overlap in the Z-axis direction near the tip on the + Y-axis side of the first piezoelectric element 140.

  FIG.15 (b) is DD sectional drawing of Fig.15 (a). The second piezoelectric element 350 includes a second lower electrode film 351 formed on the surface of the second arm 330 on the + Z-axis side and a second piezoelectric film formed on the + Z-axis side of the second lower electrode film 351. 352 and the second upper electrode film 353 formed on the + Z-axis side of the second piezoelectric film 352. The length of the first arm 120 in the Y-axis direction is defined as a length L1, and the thickness in the Z-axis direction is defined as a thickness T1. Further, the length of the second arm portion 330 in the Y-axis direction is defined as a length L2, and the thickness in the Z-axis direction is defined as a thickness T2. The first arm portion 120 and the second arm portion 330 are formed so that the ends on the −Y axis side are aligned, and the length L2 is shorter than the length L1. Further, the thickness T1 is formed to be thicker than the thickness T2.

  The frequency of the piezoelectric vibrating piece is proportional to the thickness of the arm and inversely proportional to the square of the length. In the piezoelectric vibrating piece 300, the length L2 is formed to be shorter than the length L1, and accordingly, the thickness T2 is formed to be thinner than the thickness T1 so as to correspond to the length L2. Adjustment is made so that the frequency with the two arms 330 is equal.

  The frequency of the piezoelectric vibrating piece may be adjusted by removing the metal film of the piezoelectric element formed at the tip of the arm, but the arm is formed so as to overlap in the Z-axis direction. It is difficult to adjust the frequency of the first arm. On the other hand, in the piezoelectric vibrating piece 300, the second arm portion 330 does not overlap in the Z-axis direction at the + Y-axis side end of the first piezoelectric element 140 formed in the first arm portion 120, so the first piezoelectric element 140 Etching using argon gas or the like can be performed on the first upper electrode film 143, thereby adjusting the frequency of the first arm 120. That is, in the piezoelectric vibrating piece 300, the second upper electrode film 353 is etched to adjust the frequency of the second arm portion 330, and the first upper electrode film 143 is shaved to adjust the frequency of the first arm portion 120. Since both can be performed, the frequency can be easily adjusted.

  As described above, the optimal embodiment of the present invention has been described in detail. However, as will be apparent to those skilled in the art, the present invention can be implemented with various modifications and variations within the technical scope thereof.

  For example, a gold (Au) film may be formed on the surfaces of the first upper electrode and the second upper electrode by sputtering or vapor deposition so that the frequency can be easily adjusted. By adjusting the frequency by cutting the gold film, the frequency can be adjusted while maintaining the excitation efficiency of each piezoelectric element formed on each arm.

  Further, for example, in the first embodiment, the through electrode 162 is formed so as to penetrate the surface on the −Z axis side of the base portion 110, and the electrode on the −Z axis side of the base portion 110 extends from the −Y axis side to the + Y axis side. The through electrode 162 is formed by extending the surface on the + Z-axis side of the base portion 110 from the −Y-axis side to the + Y-axis side, and the + Y-axis of the base portion 110 is formed (see FIG. 1A). A through electrode penetrating the base 110 may be formed on the side and electrically connected to the external electrode 172. Thus, when an electrode is also formed on the + Z-axis side of the base 110, the electrode is formed on the surface on the + Z-axis side of the substrate wafer W110 between step S102 and step S103 in FIG.

  Furthermore, the bonding of the substrate wafer and the base plate wafer (step S204 in FIG. 11) or the bonding of the substrate wafer and the lid plate wafer (step S205 in FIG. 11) in the second embodiment is performed by the sealing material 240. The bonding may be performed not only by such resin bonding but also by a bonding method such as direct bonding or anodic bonding.

DESCRIPTION OF SYMBOLS 100, 230 ... Piezoelectric vibration piece 110 ... Base 120 ... 1st arm part 130, 330 ... 2nd arm part 140 ... 1st piezoelectric element 141 ... 1st lower electrode film 142 ... 1st piezoelectric film 143 ... 1st upper part Electrode films 150, 350 ... 2nd piezoelectric element 151, 351 ... 2nd lower electrode film 152, 352 ... 2nd piezoelectric film 153, 353 ... 2nd upper electrode film 161, 162 ... Through electrode 171, 172, 224 ... External electrodes 181, 183, 234... Through grooves 182, 233... Connection portion 184... SiN film 185... First protective film layer 186... First silicon layer 187... First metal film 188. 191 ... Second protective film layer 192 ... Second silicon layer 200 ... Piezoelectric device 210 ... Lid plates 211, 221 ... Recesses 212, 222 ... Bonding surface 220 ... Base plate 223 ... Castration 225 ... Connection electrode 231 ... Vibrating part 232 ... Frame part 232a ... First frame part 232b ... Second frame part 232c ... Third frame part 235 ... Extraction electrode 240 ... Sealing material 241 ... Scribe line 242 ... Through hole W110, W230 ... Substrate wafer W210 ... Lid plate wafer W220 ... Base plate wafer

Claims (10)

A base formed in a planar shape, a first arm formed on the base and extending in the first direction, and a second arm formed on the first arm and extending in the first direction. A method of manufacturing a piezoelectric vibrating piece in which one end of the first arm is connected to one end of the base and the second arm,
A first protective film layer forming step of forming a first protective film layer on a substrate wafer on which a plurality of the bases are formed;
A first silicon layer forming step of forming a first silicon layer constituting the first arm portion on the first protective film layer;
A first lower electrode film formed on the first silicon layer, a first piezoelectric film formed on the first lower electrode film, and a first upper electrode film formed on the first piezoelectric film A first piezoelectric element forming step of forming a first piezoelectric element constituted by:
A second protective film layer forming step of forming a second protective film layer on the first piezoelectric element;
A second silicon layer forming step of forming a second silicon layer constituting the second arm portion on the second protective film layer;
A second lower electrode film formed on the second silicon layer; a second piezoelectric film formed on the second lower electrode film; and a second upper electrode film formed on the second piezoelectric film A second piezoelectric element forming step of forming a second piezoelectric element constituted by:
And a protective film layer removing step of removing all of the first protective film layer and the second protective film layer by etching.   The first piezoelectric element and the second piezoelectric element formed on each piezoelectric vibrating piece are formed to have the same area and the same shape, and are formed so as to overlap each other in the vertical direction. Manufacturing method of the piezoelectric vibrating piece.   The method for manufacturing a piezoelectric vibrating piece according to claim 1, wherein the first arm portion is formed longer in the first direction than the second arm portion. The piezoelectric vibrating piece is formed in a state of being connected to the substrate wafer via a connecting portion,
4. The piezoelectric vibrating piece separating step according to claim 1, further comprising a step of separating the piezoelectric vibrating piece by separating the piezoelectric vibrating piece from the substrate wafer by folding the connecting portion after the protective film layer removing step. A method for manufacturing a piezoelectric vibrating piece according to any one of the preceding claims. The piezoelectric vibrating piece includes a vibrating part including the base, the first arm part, and the second arm part, a frame part formed so as to surround the vibrating part, and the vibrating part And a connecting portion that connects the frame portion, and a method of manufacturing a piezoelectric device in which the piezoelectric vibrating piece is formed between a base plate and a lid plate,
A base plate in which the substrate wafer and the base plate are formed after the piezoelectric vibrating piece is formed on the substrate wafer by the method of manufacturing a piezoelectric vibrating piece according to any one of claims 1 to 3. A base plate wafer bonding step for bonding the wafer;
A lid plate wafer bonding step for bonding the substrate wafer and the lid plate wafer on which the lid plate is formed;
A cutting method of cutting the substrate wafer, the base plate wafer, and the lid plate wafer. A base formed in a planar shape;
A first arm portion of a free end that is formed to extend in a first direction, one end is fixed on the base, and the other end is not fixed;
A second arm portion of a free end that is formed to extend in the first direction, one end is fixed on the one end of the first arm portion, and the other end is not fixed;
A first lower electrode film formed on one surface of the first arm, a first piezoelectric film formed on the first lower electrode film, and a first formed on the first piezoelectric film. A first piezoelectric element constituted by one upper electrode film;
A second lower electrode film formed on one surface of the second arm part; a second piezoelectric film formed on the second lower electrode film; and a second electrode formed on the second piezoelectric film. And a second piezoelectric element configured by the upper electrode film.   The piezoelectric vibrating piece according to claim 6, wherein the first piezoelectric element and the second piezoelectric element are formed to have the same area and the same shape, and overlap each other in the vertical direction.   The piezoelectric vibrating piece according to claim 6, wherein the first arm portion is formed longer in the first direction than the second arm portion. A vibration portion formed including the base, the first arm, the second arm, the first piezoelectric element, and the second piezoelectric element;
A frame portion formed so as to surround the periphery of the vibrating portion;
The piezoelectric vibrating piece according to claim 6, further comprising a connecting portion that connects the vibrating portion and the frame portion. The piezoelectric vibrating piece according to claim 9,
A base plate joined to one surface of the frame part;
And a lid plate joined to the other surface of the frame portion.